NASA James Hansen, Gavin Schmidt Paper: 10 More Years of Global Warming Pause (Maybe)

Guest essay by Eric Worrall

h/t Benny Peiser / GWPF – Former NASA GISS Director James Hansen and current director Gavin Schmidt think nature may conspire of the next ten years to produce the impression of an ongoing pause in global warming. Though of course it may not.

Global Temperature in 2017

18 January 2018
James Hansen, Makiko Sato, Reto Ruedy, Gavin A. Schmidt, Ken Lo, Avi Persin

Abstract. Global surface temperature in 2017 was the second highest in the period of instrumental measurements in the Goddard Institute for Space Studies (GISS) analysis. Relative to average temperature for 1880-1920, which we take as an appropriate estimate of “pre-industrial” temperature, 2017 was +1.17°C (~2.1°F) warmer than in the 1880-1920 base period. The high 2017 temperature, unlike the record 2016 temperature, was obtained without any boost from tropical El Niño warming.

Prospects for continued global temperature change are more interesting and important. The record 2016 temperature was abetted by the effects of both a strong El Niño and maximum warming from the solar irradiance cycle (Fig. 4). Because of the ocean thermal inertia and decadal irradiance change, the peak warming and cooling effects of solar maximum and minimum are delayed about two years after irradiance extrema. The amplitude of the solar irradiance variation is smaller than the planetary energy imbalance, which has grown to about +0.75 ± 0.25 W/m2 over the past several decades due to increasing atmospheric greenhouse gases.5,6 However, the solar variability is not negligible in comparison with the energy imbalance that drives global temperature change. Therefore, because of the combination of the strong 2016 El Niño and the phase of the solar cycle, it is plausible, if not likely, that the next 10 years of global temperature change will leave an impression of a ‘global warming hiatus’.

On the other hand, the 2017 global temperature remains stubbornly high, well above the trend line (Fig. 1), despite cooler than average temperature in the tropical Pacific Niño 3.4 region (Fig. 5), which usually provides an indication of the tropical Pacific effect on global temperature. Conceivably this continued temperature excursion above the trend line is not a statistical fluke, but rather is associated with climate forcings and/or feedbacks. The growth rate of greenhouse gas climate forcing has accelerated in the past decade. There is also concern that polar climate feedbacks may accelerate.

Therefore, temperature change during even the next few years is of interest, to determine whether a significant excursion above the trend line is underway.

Read more: http://www.columbia.edu/~jeh1/mailings/2018/20180118_Temperature2017.pdf

Will temperatures rise or fall over the next decade? Temperatures could rise, stagnate or even fall (if solar factors prove a little stronger than expected) according to Schmidt and Hansen’s each way bet. Though they claim that real global warming, the planetary “energy imbalance”, will still be occurring under the cover of whatever happens to global temperature.

The latest prediction does extend the period in which Hansen and Schmidt’s theories cannot be falsified by temperature observations. Up, down or sideways, this paper covers their butts.

This isn’t the first time Hansen has slipped in a prediction that global temperatures will be forced down, despite CO2 driven warming. The diagram at the top of the page is from a previous Hansen paper J. Hansen et al.: Ice melt, sea level rise and superstorms, in which Hansen predicted a possible abrupt drop in global temperature in the near future, caused by ice melt shutting down global ocean currents.

Is this paper really what passes for “settled science” these days? If I was a Congressman the question I would be asking, is a “settled science” prediction that temperatures could go up, down or sideways really good value for taxpayer’s money?

Why doesn’t the US Government save some taxpayer’s money, ask Punxsutawney Phil for his climate predictions, instead of continuing to pay NASA GISS for their each way bets? Punxsutawney Phil might get it wrong sometimes, but at least the theory that Punxsutawney Phil makes good predictions is falsifiable – Phil’s predictions can be compared to temperature observations.

via Watts Up With That?

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January 24, 2018 at 06:01PM

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